Timing Chain Tensioner - E36 M3, E46 M3, MZ3, Z4M

This is the Genuine BMW timing chain tensioner for the S52 and S54 engines in the E36 M3, E46 M3, all MZ3, and Z4M. If your engine produces a rattle sound on startup that goes away within a minute this tensioner is a likely source. The tensioner relies on an internal spring when the engine is cold (and oil is not yet flowing) to set the tension on the timing chain. Once oil is circulating, oil pressure takes over the tension. A weak spring will cause chain rattle.

Do not confuse chain rattle/slap with any other more serious rattles, such as VANOS or timing chain guides (S54). The timing chain tensioner mostly relies on oil pressure so it will reach proper tension quickly. Prolonged rattles from the front of the engine may indicate a problem somewhere else.

This is a Genuine BMW S52/S54 chain tensioner with a two year warranty. Buying a Genuine part will usually be more expensive than an OEM or aftermarket brand but you are assured that it meets BMW's designs for fitment, performance, and longevity. It will also be the very latest design, incorporating any updates or revisions that an aftermarket brand typically will ignore.